Is melamine the next dangerous kitchen chemical?

NEW YORK (Reuters Health) - A chemical that sickened and killed babies in China when it tainted baby formula can also leach off of tableware and into food, a new small study suggests.

However, researchers said, that doesn't prove the compound, called melamine, is harmful to kids and adults in the amounts detected when study participants ate hot soup from melamine bowls.

Large doses of melamine - which is used in some types of fertilizer and in resin used to make tableware - killed six babies in China and sent thousands more to the hospital with kidney damage in 2008. In high enough quantities, melamine can cause kidney stones and other kidney problems in adults as well.

In the new study, healthy young adults who ate hot noodle soup from bowls made with melamine resin had higher levels of the chemical in their urine for the next 12 hours.

The study "raises interesting questions about environmental agents that can affect the kidney long term," said Dr. Craig Langman, who studies kidney diseases at Northwestern University's Feinberg School of Medicine in Chicago.

"It does raise some concerns, but it hardly proves anything," added Langman, who wasn't involved in the new research. "To date, I have great skepticism about the link."

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Researchers led by Chia-Fang Wu from Kaohsiung Medical University in Taiwan had six people in their 20s eat hot soup for breakfast out of melamine bowls and another six eat soup from ceramic bowls. Then, the researchers monitored participants' urine for the next 12 hours. Three weeks later, the two groups were reversed.

For the rest of the day, the total melamine excreted in study volunteers' urine was 8.35 micrograms following a melamine-bowl breakfast, compared to 1.31 micrograms after breakfast from a melamine-free bowl.

The researchers didn't measure any health effects possibly related to melamine - and it's not clear if those urine levels would lead to any long-term medical problems or if participants' bodies were storing any of the chemical.

Still, Wu and colleagues wrote in JAMA Internal Medicine, "Although the clinical significance of what levels of urinary melamine concentration has not yet been established, the consequences of long-term melamine exposure should still be of concern."

Langman said research into the chemical's long-term biological effects should continue.

"The babies who were poisoned because of their being young had very low kidney function to begin with," he told Reuters Health - so their kidneys were particularly vulnerable to the chemical.

What's more, "Clearly, poisoning acutely with this massive overload is different than long-term exposure," Langman said.

According to the Food and Drug Administration, melamine is approved in the U.S. for use in the manufacturing of some cooking utensils, tableware, plastics and industrial coatings, among other things. The chemical is likely more common in other countries including China.

"American exposure from tableware must be astonishingly small, or not at all. (However), because of the Chinese poisoning epidemic, we have to be entirely vigilant all the time about our food supply," Langman added.

He said anyone who has a choice might as well avoid buying tableware made with melamine, because it does interact with some acidic foods and in the microwave.